U.S. patent number 9,236,791 [Application Number 13/644,609] was granted by the patent office on 2016-01-12 for systems and methods for distributing power in a vehicle.
This patent grant is currently assigned to General Electric Company. The grantee listed for this patent is General Electric Company. Invention is credited to Ajith Kuttannair Kumar, Wendong Zhang.
United States Patent |
9,236,791 |
Kumar , et al. |
January 12, 2016 |
Systems and methods for distributing power in a vehicle
Abstract
Various systems and method for distributing electrical power are
provided. In one embodiment, a system includes a first inverter
coupled to an electrical bus, a second inverter coupled to the
electrical bus, a filter including a first inductor and a second
inductor, and a transfer switch circuit coupled between the first
inverter and the second inverter and a load. The transfer switch
circuit is configured to transfer power from the first inverter
through the first inductor to the load and transfer power from the
second inverter through the second inductor to the load in a first
mode of operation. The transfer switch circuit is further
configured to transfer power from the first inverter through the
first inductor and through the second inductor to the load in a
second mode of operation.
Inventors: |
Kumar; Ajith Kuttannair (Erie,
PA), Zhang; Wendong (Erie, PA) |
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Assignee: |
General Electric Company
(Schenectady, NY)
|
Family
ID: |
50432150 |
Appl.
No.: |
13/644,609 |
Filed: |
October 4, 2012 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20140097696 A1 |
Apr 10, 2014 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60L
1/16 (20130101); B60L 53/63 (20190201); B60L
50/14 (20190201); B60L 9/22 (20130101); H02M
1/126 (20130101); B60L 1/12 (20130101); H02M
7/493 (20130101); B60L 55/00 (20190201); B60L
53/65 (20190201); B60L 15/007 (20130101); H02M
7/5387 (20130101); B60L 2240/421 (20130101); Y02T
90/12 (20130101); Y02T 90/169 (20130101); Y04S
10/126 (20130101); Y04S 30/14 (20130101); B60L
2240/423 (20130101); B60L 2240/12 (20130101); B60L
2240/443 (20130101); Y02T 90/14 (20130101); B60L
2240/441 (20130101); B60L 2200/26 (20130101); B60L
2260/28 (20130101); Y02E 60/00 (20130101); Y02T
10/7072 (20130101); Y02T 10/64 (20130101); Y02T
90/16 (20130101); Y02T 10/70 (20130101); Y02T
90/167 (20130101) |
Current International
Class: |
H02M
1/12 (20060101); H02M 7/493 (20070101); B60L
1/12 (20060101); B60L 15/00 (20060101); B60L
9/22 (20060101); B60L 11/10 (20060101); B60L
11/18 (20060101); H02M 7/5387 (20070101); B60L
1/16 (20060101) |
Field of
Search: |
;307/83,104 ;320/63 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Fureman; Jared
Assistant Examiner: Pacheco; Rafael
Attorney, Agent or Firm: GE Global Patent Operation Kramer;
John A.
Claims
The invention claimed is:
1. A system, comprising: a first inverter coupled to an electrical
bus; a second inverter coupled to the electrical bus; a filter
including a first inductor and a second inductor; a transfer switch
circuit coupled between the first inverter and the second inverter
and a load; and a controller having instructions to control the
transfer switch circuit to transfer power from the first inverter
through the first inductor to the load and transfer power from the
second inverter through the second inductor to the load in a first
mode of operation, and to transfer power from the first inverter
through the first inductor and through the second inductor to the
load in a second mode of operation.
2. The system of claim 1, wherein the transfer switch circuit is
further configured to transfer power from the second inverter
through the first inductor and through the second inductor to the
load in a third mode of operation.
3. The system of claim 2, wherein the transfer switch circuit is
configured to transfer substantially no power from the first
inverter to the load in the third mode of operation.
4. The system of claim 2, wherein the transfer switch circuit
comprises a first contact, a second contact, a third contact, a
fourth contact, and a fifth contact, and the controller further
includes instructions to control the transfer switch circuit to:
transfer power from the first inverter through the third contact
and through the first inductor to the load, and transfer power from
the first inverter through the third contact, through the fourth
contact, and through the second inductor to the load in the second
mode of operation, and transfer power from the second inverter
through the fifth contact and through the second inductor to the
load, and transfer power from the second inverter through the fifth
contact, through the fourth contact, and through the first inductor
to the load in the third mode of operation.
5. The system of claim 1, wherein the transfer switch circuit
comprises a first contact, a second contact, a third contact, and a
fourth contact, the controller further having instructions to
control the transfer switch circuit to: transfer power from the
first inverter through the first contact and through the first
inductor to the load, and transfer power from the second inverter
through the second contact and through the second inductor to the
load in the first mode of operation, and transfer power from the
first inverter through the third contact and through the first
inductor to the load, and transfer power from the first inverter
through the third contact, through the fourth contact, and through
the second inductor to the load in the second mode of
operation.
6. The system of claim 1, wherein the filter is coupled between the
first and second inverters and the transfer switch circuit.
7. The system of claim 1, wherein the filter is coupled between the
transfer switch circuit and the load.
8. The system of claim 1, wherein the transfer switch circuit is
configured to transfer substantially no power from the second
inverter to the load in the second mode of operation, wherein the
electrical bus is coupled to an alternator, and wherein the
controller has instructions to switch from the first mode of
operation to the second mode of operation based on an output of the
alternator.
9. A system, comprising: a first inverter coupled to an electrical
bus; a second inverter coupled to the electrical bus; and a
transfer switch circuit coupled to the first inverter, the second
inverter, and a load, the transfer switch circuit being configured
to transfer power from the first inverter through a first contact
to the load and transfer power from the second inverter through a
second contact to the load in a first mode of operation, the
transfer switch circuit further being configured to divide power
from the first inverter between a third contact and a fourth
contact in parallel to the load in a second mode of operation.
10. The system of claim 9, wherein the transfer switch circuit is
configured to transfer substantially no power from the second
inverter to the load in the second mode of operation.
11. The system of claim 9, wherein the transfer switch circuit is
configured to divide power from the second inverter between the
second contact and a fifth contact in parallel to the load in a
third mode of operation.
12. The system of claim 11, wherein the transfer switch circuit is
configured to transfer substantially no power from the first
inverter to the load in the third mode of operation.
13. The system of claim 11, further comprising: a filter including
a first inductor and a second inductor, and wherein the transfer
switch circuit is configured to transfer power from the first
inverter through the first contact and through the first inductor
to the load and transfer power from the second inverter through the
second contact and through the second inductor to the load in the
first mode of operation.
14. The system of claim 13, wherein the transfer switch circuit is
configured to transfer power from the first inverter through the
third contact and through the first inductor to the load and
transfer power from the first inverter through the fourth contact
and through the second inductor to the load in the second mode of
operation.
15. The system of claim 13, wherein the transfer switch circuit is
configured to transfer power from the second inverter through the
second contact and through the second inductor to the load and
transfer power from the second inverter through the fifth contact
and through the first inductor to the load in the third mode of
operation.
16. The system of claim 13, wherein the filter is coupled between
the first and second inverters and the transfer switch circuit.
17. The system of claim 13, wherein the filter is coupled between
the transfer switch circuit and the load.
18. A method, comprising: controlling a transfer switch circuit, in
a first mode of operation, to transfer power from a first inverter
through a first inductor to a load and transfer power from a second
inverter through a second inductor to the load; and controlling the
transfer switch circuit, in a second mode of operation, to transfer
power from the first inverter through the first inductor and
through the second inductor to the load.
19. The method of claim 18, further comprising: controlling the
transfer switch circuit, in a third mode of operation, to transfer
power from the second inverter through the first inductor and
through the second inductor to the load.
20. The method of claim 19 further comprising, controlling the
transfer switch circuit, in the first mode of operation, to
transfer power from the first inverter through a first contact of
the transfer switch circuit and through the first inductor to the
load and transfer power from the second inverter through a second
contact of the transfer switch circuit and through the second
inductor to the load; controlling the transfer switch circuit, in
the second mode of operation, to transfer power from the first
inductor through a third contact and through the first inductor to
the load and transferring power from the first inductor through the
third contact, through a fourth contact, and through the second
inductor to the load, and transfer substantially no power from the
second inverter to the load; and controlling the transfer switch
circuit, in the third mode of operation, to transfer power from the
second inductor through a fifth contact and through the second
inductor to the load, transfer power from the second inductor
through the fifth contact, through the fourth contact, and through
the first inductor to the load, and transfer substantially no power
from the first inverter to the load during the third mode of
operation.
Description
FIELD
Embodiments of the subject matter disclosed herein relate to
systems and methods for distributing electrical power from an
inverter circuit in a vehicle.
BACKGROUND
In some vehicles, an engine may be coupled to an alternator to
generate electrical power for various components. For example, a
locomotive or a generator car may include a head-end-power or
hotel-electric-power (HEP) alternator that distributes electrical
power to other cars in a train for lighting, electrical, and other
hotel needs of passengers. More particularly, the HEP alternator
may provide electrical power through a bus to an inverter circuit.
For example, the inverter circuit may include dual inverters that
convert direct current (DC) power from the bus to alternating
current (AC) power that is provided to other cars and various
electrical components.
In one example, the dual inverter circuit may be controlled by a
three-position transfer switch circuit that enables the dual
inverters to operate in parallel, or each in standalone operation
depending on operating conditions. FIGS. 11-12 show a PRIOR ART
transfer switch circuit 1100 in different operating positions. FIG.
11 shows the transfer switch circuit 1100 in a parallel operating
position (e.g., middle position) where power is provided from each
of a first inverter 1102 and a second inverter 1108 to a load 1114.
In particular, the first inverter 1102 provides power through a
first contact 1104 and through a first inductor 1106 to the load
1114. Further, the second inverter 1108 provides power through a
second contact 1110 and through a second inductor 1112 to the load
1114.
FIG. 12 shows the transfer switch circuit 1100 in a standalone
operating position (e.g., top position) where power is provided
from the first inverter 1102 to the load 1114. In this position,
the second inverter 1108 does not provide power to the load 1114.
In particular, the first inverter 1102 provides power through a
third contact 1116 and through the first inductor 1106 to the load
1114.
In some cases, a power transfer capability of the transfer switch
circuit 1100 may be restricted due to the layout of the transfer
switch. For example, when the transfer switch circuit 1100 is in
the standalone operating position, all of the power from the first
inverter (and the bus) passes through the third contact 1116 and
first inductor 1106. In other words, the power transfer circuit
1100 provides no current sharing capabilities between contacts
while in the standalone operating position. Moreover, the power
transfer circuit 1100 provides no current sharing capabilities
between inductors while in the standalone operating position.
Because of such power demands on the single contact of the transfer
switch and the single inductor while in the standalone operation
position, power transferred through the switch to the load may be
restricted in order to reduce the likelihood of degradation of that
contact and the inductor.
BRIEF DESCRIPTION OF THE INVENTION
In one embodiment, a system includes a first inverter coupled to an
electrical bus, a second inverter coupled to the electrical bus, a
filter including a first inductor and a second inductor, and a
transfer switch circuit coupled between the first inverter and the
second inverter and a load. The transfer switch circuit is
configured to transfer power from the first inverter through the
first inductor to the load and transfer power from the second
inverter through the second inductor to the load in a first mode of
operation. The transfer switch circuit is further configured to
transfer power from the first inverter through the first inductor
and through the second inductor to the load in a second mode of
operation.
The system, and more particularly, the transfer switch circuit,
provides even power sharing among inductors throughout multiple
modes of operation, such that no one inductor receives enough
current to cause degradation. In particular, in the standalone mode
of operation where power from one inverter is provided to the load,
power from the inverter is divided evenly between the two
inductors. In this way, the power transfer capability of the
transfer switch circuit can be increased relative to the transfer
switch circuit 1100 where all power from an inverter flows through
a single inductor when operating in the standalone position.
It should be understood that the brief description above is
provided to introduce in simplified form a selection of concepts
that are further described in the detailed description. It is not
meant to identify key or essential features of the claimed subject
matter, the scope of which is defined uniquely by the claims that
follow the detailed description. Furthermore, the claimed subject
matter is not limited to implementations that solve any
disadvantages noted above or in any part of this disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be better understood from reading the
following description of non-limiting embodiments, with reference
to the attached drawings, wherein below:
FIG. 1 shows a schematic diagram of a rail vehicle according to an
embodiment of the present disclosure.
FIG. 2 shows a schematic diagram of a power distribution circuit
according to an embodiment of the present disclosure.
FIG. 3 shows a schematic diagram of another power distribution
circuit according to an embodiment of the present disclosure.
FIG. 4 shows a schematic diagram of transfer switch circuit
operating in a first mode where two inverters provide power through
the transfer switch circuit to a load in parallel operation.
FIG. 5 shows a schematic diagram of the transfer switch circuit of
FIG. 4 operating in a second mode where a first inverter provides
power through the transfer switch circuit in standalone
operation.
FIG. 6 shows a schematic diagram of the transfer switch circuit of
FIG. 4 operating in a third mode where a second inverter provides
power through the transfer switch circuit in standalone
operation.
FIG. 7 shows a schematic diagram of another transfer switch circuit
operating in a first mode where two inverters provide power through
the transfer switch circuit to a load in parallel operation.
FIG. 8 shows a schematic diagram of the transfer switch circuit of
FIG. 6 operating in a second mode where a first inverter provides
power through the transfer switch circuit in standalone
operation.
FIG. 9 shows a schematic diagram of the transfer switch circuit of
FIG. 6 operating in a third mode where a second inverter provides
power through the transfer switch circuit in standalone
operation.
FIG. 10 shows a flow chart of an example method for controlling a
transfer switch circuit.
FIGS. 11-12 show schematic diagrams of a PRIOR ART transfer switch
circuit.
DETAILED DESCRIPTION
The present description relates to various embodiments of systems
and methods for distributing electrical power in a vehicle. More
particularly, the present description relates to a transfer switch
circuit that is configured to transfer power from a dual inverter
circuit to a load. The transfer switch circuit operates in
different modes (or positions) of operation where power paths are
evenly shared between different inductors and/or different switch
contacts in each of the modes of operation.
In one example, a train may include a plurality of rail vehicles
interconnected with one another. In some examples, one rail vehicle
may generate electrical power and transmit the electrical power to
other rail vehicles in the train. Such power may be generated in a
head-end-power or hotel-electric-power (HEP) system. The HEP system
may provide power to a HEP bus. The dual inverter circuit may be
coupled to the HEP bus to modify the power on the HEP bus to a
suitable form to be distributed to the plurality of rail vehicles
(e.g., converter direct current (DC) power to alternating current
(AC) power) that may be referred to in some cases as a load on the
HEP bus. Further, the transfer switch circuit may be coupled
between the dual inverter circuit and the load to control power
transfer from the HEP bus to the load.
FIG. 1 schematically shows an embodiment of a vehicle system 100,
herein depicted as a rail vehicle, configured to run on a rail 102
using a plurality of wheels 104. In one example, the rail vehicle
100 is a locomotive. In another example, the rail vehicle 100 is a
generator car that is not a locomotive. In some embodiments, the
vehicle system 100 may be coupled to a plurality of rail cars 136
that are connected to form a train. In one example, the train is a
passenger train that includes one or more locomotives coupled to
one or more passenger cars. The rail vehicle 100 includes an engine
system 106. In other non-limiting embodiments, the engine system
106 is a stationary engine system, such as in a power-plant
application, while in yet other applications, the engine is used in
a ship, on-highway vehicle, off-highway vehicle, or other
propulsion system. The engine system 106 is operable to generate
electrical power for distribution to various components, modules,
cars, etc. that may be remotely located from the engine system
106.
In one example, the rail vehicle 100 is a diesel-electric vehicle.
For example, the engine system 106 includes a diesel engine 108
that generates a torque output on a drive shaft 112 that is
transmitted to an electrical power generation unit 114. In some
embodiments, the engine 108 is a four-stroke engine in which each
of the cylinders fires in a firing order during two revolutions of
the drive shaft 112. In other embodiments, the engine 108 is a
two-stroke engine in which each of the cylinders fires in a firing
order during one revolution of the drive shaft 112.
The electrical power generation unit 114 produces electrical power
that is applied for subsequent propagation to a variety of
downstream electrical components. The electrical power generation
unit 114 includes a traction alternator 116, a HEP alternator 118,
and an auxiliary alternator 120. As described herein, the
alternators of the electrical power generation unit 114 may also be
referred to individually as power distribution units, power
systems, or power circuits. Each of the traction alternator 116,
the HEP alternator 118, and the auxiliary alternator 120 are
coupled to the drive shaft 112 to convert torque output from the
engine 108 into electrical power to be distributed to various
components.
In the illustrated embodiment, the traction alternator 116, the HEP
alternator 118, and the auxiliary alternator 120 are positioned in
the same physical housing of the electrical power generation unit
114. However, it will be appreciated that in some embodiments, one
or more of the alternators may be located elsewhere in the rail
vehicle. For example, in some embodiments, the engine system of the
rail vehicle may include a second engine and one or more of the
alternators may be coupled to a drive shaft of the second
engine.
The traction alternator 116 provides electrical power to a
plurality of fraction motors 110. As depicted, the plurality of
fraction motors 110 are each connected to one of a plurality of
wheels 104 to provide tractive power to propel the rail vehicle
100. One example rail vehicle configuration includes one traction
motor per wheel pair (axle). As depicted herein, six traction
motors correspond to each of six pairs of wheels of the rail
vehicle. The fraction alternator 116 and associated electronic
components will be discussed in further detail below with reference
to FIG. 2.
The HEP alternator 118 provides electrical power to a plurality of
rail cars 136 coupled to the rail vehicle 100 through a contactor
122. In one example, the plurality of rail cars includes unpowered
cars, such as passenger cars, dining cars, etc. For example,
electrical power provided by the HEP alternator 118 may supply the
lighting, HVAC, dining car kitchen, battery charging loads, and
other hotel needs of connected rail cars. In another example, the
unpowered cars use the electrical power provided by the HEP
alternator for heating, lighting, ventilation, air conditioning,
communication equipment, entertainment devices, fans,
outlets/sockets, or kitchen equipment. As used herein, a HEP
alternator refers to an alternator that generates electrical power
in a first rail vehicle that is transmitted to, and consumed by,
electrical loads positioned in other rail vehicles that are
mechanically coupled to, either directly or indirectly, the first
rail vehicle in a train.
In some embodiments, the vehicle system is one of a plurality of
vehicles coupled together and the HEP alternator provides power to
some or all of the plurality of coupled vehicles. In one example,
the vehicle system is a one of a plurality of locomotives or other
rail vehicles in a consist. (A consist is a group of vehicles that
are mechanically coupled to travel together along a route.) As
another example, the vehicle system is one generator car in a set
of generator cars across one or more locomotives in a consist. In
such embodiments, a HEP load may be balanced between the plurality
of vehicles. In one example, the HEP load is balanced between the
plurality of vehicles to maintain a designated horse power and/or a
fuel consumption rate. In one example, the HEP load may be in a
range from about 20 kW to more than 150 kW, or up to 560 kW. In
other examples, the HEP load may have a voltage range from 800 V to
1000 V AC/DC two pole (400 or 600 A), 1500 V AC two pole (800 A) or
at 415 V three-phase, 380 V three-phase, three-phase AC at 480 V,
or switchable between voltages: e.g., 1,000 V AC 162/3 Hz, 1,500 V
AC 50 Hz, 1,500 V DC and 3,000 V DC. In one particular example, the
HEP alternator supplies three-phase AC electrical power at 480 V
and 60 Hz. In some embodiments, transformers may be fitted in each
rail car to lower voltages for consumption by various onboard
devices.
The HEP system 118 provides power to various electrical components
through a HEP bus 148. For example, the HEP alternator may produce
AC power that is converted to DC power by a rectifier and supplied
to the HEP bus 148. A dual inverter circuit 144 is coupled to the
HEP bus 148. The dual inverter circuit 144 includes two inverters
configured to modify the electrical power received from the HEP bus
148 to a suitable form to be provided to the rail cars 136 of the
rail vehicle 100. In particular, the dual inverter circuit 144
converts DC power to AC power, among other modifications. It will
be appreciated that other inverter circuits having a different
amount of inverters may be employed without departing from the
scope of the present disclosure.
A transfer switch circuit 146 is positioned between the dual
inverter circuit and the HEP load (e.g., rail cars) to control the
supply of current to the HEP load. The transfer switch circuit 146
may be operable in three different modes of operation depending on
operating conditions. Specifically, the transfer switch circuit is
operable in a first mode of operation that enables a first inverter
and a second inverter to operate in parallel, a second mode of
operation that enables standalone operation of the first inverter,
and a third mode of operation that enables standalone operation of
the second inverter. The transfer switch circuit is configured such
that power is shared equally between active switch contacts in each
of the modes of operation. The transfer switch circuit will be
described in further detail with reference to FIGS. 4-6.
A HEP filter 150 is coupled to the HEP transfer switch circuit 146.
The HEP filter 150 reduces current that does not have a
predetermined frequency or a frequency that falls outside a
predetermined range of frequencies. For example, inductors are used
to limit current slew rate and provide filtering with capacitors to
the load. In one example, the HEP filter includes a first inductor,
a second inductor, a first capacitor, and a second capacitor. The
inductors and capacitors form LC circuits that tune a frequency of
the power output by the dual inverter circuit 144. The AC power
output from the HEP filter 150 is distributed to the rail cars 136
through the contactor 122. It will be appreciated that additional
inverters, filters, and/or other electric loads may be joined to
the HEP bus to draw current from the HEP bus and may be considered
as part of the HEP load. For example, the additional electric loads
may be fans, blowers, compressors, electronic devices, and the
like.
The auxiliary alternator 120 provides electrical power to one or
more auxiliary components 124 of the engine system 106. For
example, an auxiliary component may include a radiator fan, an
alternator blower, an inverter blower, a resistive grid blower, a
cooling tower blower, or another component associated with
operation of the engine system 106.
In some embodiments, an energy storage system 138 may be coupled to
the electrical power generation unit 114. The energy storage system
138 may be operable to receive power from any of the alternators in
the electrical power generation unit and provide power to any of
the power distribution systems associated with the alternators. In
one example, the energy storage system 138 may be operable to
receive power from the HEP alternator 118 when available, and
provide power to an electrical component coupled to the HEP
alternator when the HEP alternator does not provide power to the
electrical component. In one example, the HEP alternator may not
provide power to the electrical component because the power may be
provided to traction motors or may be used elsewhere. For example,
the electrical component may include one or more of the plurality
of cars coupled to the HEP alternator, or an auxiliary blower or
other component coupled to a HEP bus. It will be appreciated that
energy storage system 138 may include a battery and/or another
suitable power storage device.
In some embodiments, the traction motors 110 may have regenerative
power producing capabilities, such as power produced during
regenerative braking operations. As such, the vehicle system 100
may be configured to feed power produced during regenerative
operation to the HEP system, under some conditions. In particular,
regenerative power may be provided to the HEP bus to meet a HEP
load.
In some embodiments, the vehicle system 100 includes a pantograph
140 that is coupled to an overhead power line 142. The pantograph
140 collects power from the overhead power line 142 when available
to be used for various operations. The pantograph 140 is coupled to
the power generation unit 114 to provide power to the various power
systems including the HEP system. In one example, the pantograph
140 is operable to provide power to a hotel load on a HEP bus when
available. Further the HEP alternator is operable to provide power
to the hotel load when the pantograph does not provide power to the
hotel load.
A controller 126 at least partially controls operation of the rail
vehicle 100 and the engine system 106. The controller 126 includes
a microprocessor unit (e.g., a processor) 128 and an electronic
storage medium (a.k.a., a computer-readable storage medium) 130.
For example, the computer-readable storage medium includes one or
more of a read-only memory chip, random access memory, etc. The
computer readable storage medium 130 holds instructions that when
executed by the microprocessor unit 128 executes programs for
controlling operation of the engine system 106 as well as methods
discussed in further detail below with reference to FIG. 9. The
controller 126, while overseeing control and management of the
vehicle system 100, is configured to receive signals from a variety
of engine sensors 132 in order to determine operating parameters
and operating conditions, and correspondingly adjust various
actuators 134 to control operation of the rail vehicle 100.
In one example, the controller 126 may control operation of the
transfer switch circuit 146 into different modes of operation where
power transferred through the transfer switch circuit is shared
equally between inductors of the HEP filter 150 in each of the
modes of operation. In particular, the controller 126 is configured
to operate that transfer switch circuit 146 in a first mode of
operation, where the transfer switch circuit 146 is configured to
transfer power from the first inverter of the dual inverter circuit
144 through the transfer switch circuit 146 and through a first
inductor of the HEP filter 150 to the HEP load and transfer power
from the second inverter of the dual inverter circuit 144 through
the transfer switch circuit 146 and through a second inductor of
the HEP filter 150 to the HEP load.
Further, the controller 126 is configured to operate the transfer
switch circuit 146 in a second mode of operation, where the
transfer switch circuit 146 is configured to divide power from the
first inverter of the dual inverter circuit 144 between the first
inductor and the second inductor of the HEP filter 150 to the load
in parallel and transfer substantially no power from the second
inverter to the HEP load.
Further still, the controller 126 is configured to operate the
transfer switch circuit 146 in a third mode of operation, where the
transfer switch circuit 146 is configured to divide power from the
second inverter of the dual inverter circuit 144 between the first
inductor and the second inductor of the HEP filter 150 to the load
in parallel and transfer substantially no power from the first
inverter to the HEP load.
The controller 126 may control the transfer switch circuit to
switch modes of operation based on operating conditions. In one
example, the controller 126 adjusts the transfer switch circuit
from operating in the first mode to the second or third mode based
on the HEP load. Further, the controller 126 may switch between the
second and third modes of operation to maintain even wear and/or
heating of the first and second inverters of the dual inverter
circuit 144. In another example, the controller 126 adjusts the
transfer switch circuit between the first mode and the second or
third mode based on an output of the HEP alternator 118.
In another example, the controller 126 may control operation of the
transfer switch circuit 146 into different modes of operation where
power transferred through the transfer switch circuit is shared
equally between active switch contacts in each of the modes of
operation. In particular, the controller 126 is configured to
operate the transfer switch circuit 146 in a first mode of
operation, where the transfer switch circuit 146 is configured to
transfer power from the first inverter of the dual inverter circuit
144 through a first contact of the transfer switch circuit 146 to
the HEP load and transfer power from the second inverter of the
dual inverter circuit 144 through a second contact of the transfer
switch circuit 146 to the HEP load.
Further, the controller 126 is configured to operate the transfer
switch circuit 146 in a second mode of operation, where the
transfer switch circuit 146 is configured to divide power from the
first inverter of the dual inverter circuit 144 between a third
contact and a fourth contact to the load in parallel and transfer
substantially no power from the second inverter to the HEP
load.
Further still, the controller 126 is configured to operate the
transfer switch circuit 146 in a third mode of operation, where the
transfer switch circuit 146 is configured to divide power from the
second inverter of the dual inverter circuit 144 between the second
contact and a fifth contact to the load in parallel and transfer
substantially no power from the first inverter to the HEP load.
FIG. 2 shows a schematic diagram of a power distribution circuit
200 according to an embodiment of the present disclosure. In one
example, the power distribution circuit 200 may be implemented in
as part of the HEP system 118 shown in FIG. 1 to distribute power
to a HEP load that may include one or more rail cars of a train,
for example. The power distribution circuit 200 includes a dual
inverter circuit 204 coupled to a power bus 202. In the illustrated
embodiment, the power bus 202 is a DC bus, and the dual inverter
circuit 204 converts DC power from the power bus 202 to AC power to
be distributed to a load 222. The dual inverter circuit 204
includes a first inverter 206 and a second inverter 210 connected
in parallel to the power bus 202. The parallel configuration allows
for a higher current rating relative to a single inverter. For
example, the dual inverter circuit 204 is one non-limiting example
of the dual inverter circuit 144 shown in FIG. 1.
In the illustrated embodiment, the first inverter 206 includes a
plurality of transistors 208 that are arranged as three
single-phase inverter switches each connected to one of three
output terminals. The operation of the three switches is
coordinated so that one switch operates at each 60 degree point of
the fundamental output waveform to provide three-phase AC output.
Likewise, the second inverter 210 includes a plurality of
transistors 212 that are arranged as three single-phase inverter
switches each connected to one of three output terminals. The
operation of the three switches is coordinated so that one switch
operates at each 60 degree point of the fundamental output waveform
to provide three-phase AC output. In one example, the output
waveform of the dual inverter circuit 204 is phase shifted to
obtain a 12-step waveform when operating in parallel. It will be
appreciated that other suitable inverter circuit configurations may
be implemented without departing from the scope of the present
disclosure.
A transfer switch circuit 214 is coupled to an output of the dual
inverter circuit 204. The transfer switch circuit 214 is configured
to operate in three different modes of operation based on operating
conditions, such as HEP alternator output, HEP load, component
temperature, etc. In particular, the transfer switch circuit 214
enables the circuit topology of the dual inverter circuit 204 to
operate the first and second inverters 206 and 210 in parallel,
during a first mode of operation; operate the first inverter 206 in
standalone operation, during a second mode of operation; and
operate the second inverter 210 in standalone operation, during a
third mode of operation. Standalone operation means that one
inverter provides power to an output of the transfer switch circuit
and the other inverter does not provide power to an output of the
transfer switch circuit. For example, the transfer switch circuit
214 is one non-limiting example of the transfer switch circuit 146
shown in FIG. 1.
A filter 216 is coupled to an output of the transfer switch circuit
214. The filter 216 is configured to attenuate high voltages above
a designated level while limiting a slew rate of the output. In
particular, the filter 216 includes a plurality of inductors 218
coupled between the transfer switch circuit 214 and the load 222.
The plurality of inductors 218 block high-frequency signals and
conduct low-frequency signals. Further, the filter 216 includes a
plurality of capacitors 220 coupled between the plurality of
inductors 218 and the load 222 to provide a path to ground. The
plurality of capacitors 220 block low-frequency signals and conduct
high-frequency signals. The filter 216 may be configured to output
a designated power level that is tuned based on the load 222. For
example, the filter 216 is one non-limiting example of the filter
150 shown in FIG. 1.
FIG. 3 shows a schematic diagram of a power distribution circuit
300 according to another embodiment of the present disclosure.
Components of the power distribution circuit 200 that may be
substantially the same as those of the power distribution circuit
300 are identified in the same way and are described no further.
However, it will be noted that components identified in the same
way in different embodiments of the present disclosure may be at
least partly different. The power distribution circuit 300 may be
functionally equivalent to the power distribution circuit 200.
However, in the power distribution circuit 300, the filter 316 is
coupled between an output of the dual inverter circuit 304 and an
input of the transfer switch circuit 314, and the transfer switch
circuit 314 is coupled between the filter 316 and the load 322. In
the illustrated embodiment, power from the dual inverter circuit
304 is tuned or attenuated by the filter 316 before the power flows
to the transfer switch circuit 314.
FIGS. 4-6 show schematic diagrams of a transfer switch circuit 400
operating in different modes or positions according to an
embodiment of the present disclosure. For example, the transfer
switch circuit 400 is one non-limiting example of the transfer
switch circuit 314 shown in FIG. 3, the transfer switch circuit 214
shown in FIG. 2, or the transfer switch circuit 146 shown in FIG.
1. The transfer switch circuit 400 is configured to share current
evenly between inductors in each mode of operation. The transfer
switch circuit 400 includes a first input 422 coupled to a first
inverter 402 and a second input 424 coupled to a second inverter
408. Further, the transfer switch circuit 400 includes a first
output 426 coupled to a load 414 through a first inductor 406 and a
second output 428 coupled to the load 414 through a second inductor
412. A first capacitor 430 and a second capacitor 432 are coupled
between the first and second inductors 406 and 412 and the load
414. The transfer switch circuit 400 includes a first contact 404,
a second contact 410, a third contact 416, a fourth contact 418,
and a fifth contact 420 that may be selectively connected between
the inputs 422 and 424 and the outputs 426 and 428 depending on a
mode of operation of the transfer switch circuit 400. In
particular, the first contact 404, the third contact 416, and the
fourth contact 418 may be coupled to the first input 422 depending
on which mode/position is selected. Further, the second contact
410, the fourth contact 418, and the fifth contact 420 may be
coupled to the second input 424 depending on which mode/position is
selected.
FIG. 4 shows the transfer switch circuit 400 in a first mode of
operation where the first inverter 402 and the second inverter 408
provide power through the transfer switch circuit 400 to the load
414 in parallel. In particular, in the first mode of operation, the
first contact 404 is coupled between the first input 422 and the
first output 426, which allows power from the first inverter 402 to
flow through the first contact 404 and through the first inductor
406 to the load 414. Further, the second contact 410 is coupled
between the second input 424 and the second output 428, which
allows power from the second inverter 408 to flow through the
second contact 410 and through the second inductor 412 to the load
414. Note that the third contact 416, the fourth contact 418, and
the fifth contact 420 are not active (i.e., they do not provide
power to an output) in the first mode. In the first mode, since
both inverters provide power to the load in parallel, the total
power received from the power bus is divided between the inverters,
and the power is evenly divided between the first and second
inductors.
FIG. 5 shows the transfer switch circuit 400 operating in a second
mode of operation where the first inverter 402 provides power
through the transfer switch circuit 400 to the load 414 in
standalone operation. In particular, in the second mode of
operation, the third contact 416 is coupled between the first input
422 and the first output 426, which allows power from the first
inverter 402 to flow through the third contact 416 and through the
first inductor 406 to the load 414. Further, the fourth contact 418
is coupled between the first output 426 and the second output 428,
which allows power from the first inverter 402 to flow through the
third contact 416, through fourth contact 418 and through the
second inductor 412 to the load 414. Note that the first contact
404, the second contact 410, and the fifth contact 420 are not
active (i.e., they do not provide power to an output) in the second
mode. In the second mode, since only the first inverter provides
power to the load, the total power received from the power bus is
divided between the first and second inductors.
FIG. 6 shows the transfer switch circuit 400 operating in a third
mode of operation where the second inverter 408 provides power
through the transfer switch circuit 400 to the load 414 in
standalone operation. In particular, in the third mode, the fifth
contact 420 is coupled between the second input 424 and the second
output 428, which allows power from the second inverter 408 to flow
through the fifth contact 420 and through the second inductor 412
to the load 414. Further, the fourth contact 418 is coupled between
the second output 428 and the first output 426, which allows power
from the second inverter 408 to flow through the fifth contact 420,
through the fourth contact 418, and through the first inductor 406
to the load 414. Note that the first contact 404, the second
contact 410, and the third contact 416 are not active (i.e., they
do not provide power to an output) in the third mode. In the third
mode, since only the second inverter provides power to the load,
the total power received from the power bus is divided between the
first and second inductors.
It will be appreciated that the transfer switch circuit provides
even current sharing capabilities between the inductors in each of
the modes of operation. Accordingly, a power transfer capability of
the transfer switch circuit 400 may be increased relative to the
transfer switch circuit 1100 of FIGS. 11 and 12 that transfers all
power through a single inductor in standalone operation. Further,
it will be appreciated that the transfer switch circuit may be
implemented using contactors in addition to, or instead of transfer
switches without departing from the scope of the present
disclosure.
FIGS. 7-9 show schematic diagrams of another transfer switch
circuit 700 according to an embodiment of the present disclosure
operating in different modes or positions. For example, the
transfer switch circuit 700 is one non-limiting example of the
transfer switch circuit 314 shown in FIG. 3, the transfer switch
circuit 214 shown in FIG. 2, or the transfer switch circuit 146
shown in FIG. 1. The transfer switch circuit 700 is configured to
share current evenly between active transfer switch contacts and
inductors in each mode of operation. The transfer switch circuit
700 includes a first input 726 coupled to a first inverter 702 and
a second input 728 coupled to a second inverter 704. Further, the
transfer switch circuit 700 includes a first output 730 coupled to
a load 706 through a first inductor 718 and a second output 732
coupled to the load 706 through a second inductor 720. A first
capacitor 722 and a second capacitor 724 are coupled between the
first and second inductors 718 and 720 and the load 706. The
transfer switch circuit 700 includes a first contact 708, a second
contact 710, a third contact 712, a fourth contact 714, and a fifth
contact 716 that may be selectively connected between the inputs
726 and 728 and the outputs 730 and 732 depending on a mode of
operation of the transfer switch circuit 700. In particular, the
first contact 708, the second contact 710, and the fourth contact
714 may be coupled to the first input 726 depending on which
mode/position is selected. Further, the third contact 712, the
fourth contact 714, and the fifth contact 716 may be coupled to the
second input 728 depending on which mode/position is selected.
FIG. 7 shows the transfer switch circuit 700 in a first mode of
operation where the first inverter 702 and the second inverter 704
provide power through the transfer switch circuit 700 to the load
706 in parallel. In particular, in the first mode, the first
contact 708 is coupled between the first input 726 and the first
output 730, which allows power from the first inverter 702 to flow
through the first contact 708 and through the first inductor 718 to
the load 706. Further, the third contact 712 is coupled between the
second input 728 and the second output 732, which allows power from
the second inverter 704 to flow through the third contact 712 and
through the second inductor 720 to the load 706. Note that the
second contact 710, the fourth contact 714, and the fifth contact
716 are not active (i.e., they do not provide power to an output)
in the first mode. In the first mode of operation, since both
inverters provide power to the load in parallel, the total power
received from the power bus is divided between the inverters, and
the power is evenly divided between the active contacts (i.e., the
first contact and the third contact) of the transfer switch circuit
700. Correspondingly, each active contact carries the current of
one inductor. In particular, the first contact 708 carries the
current of the first inductor 718 and the third contact 712 carries
the current of the second inductor 720.
FIG. 8 shows the transfer switch circuit 700 operating in a second
mode of operation where the first inverter 702 provides power
through the transfer switch circuit 700 to the load 706 in
standalone operation. In particular, in the second mode, the second
contact 710 is coupled between the first input 726 and the first
output 730, which allows power from the first inverter 702 to flow
through the second contact 710 and through the first inductor 718
to the load 706. Further, the fourth contact 714 is coupled between
the first input 726 and the second output 732, which allows power
from the first inverter 702 to flow through the fourth contact 714
and through the second inductor 720 to the load 706. Note that the
first contact 708, the third contact 712, and the fifth contact 716
are not active (i.e., they do not provide power to an output) in
the second mode. In the second mode of operation, since only the
first inverter provides power to the load, the total power received
from the power bus is provided by the first inverter, and the power
is evenly divided between the active contacts (i.e., the second
contact and the fourth contact) of the transfer switch circuit 700.
Correspondingly, each active contact carries the current of one
inductor. In particular, the second contact 710 carries the current
of the first inductor 718 and the fourth contact 714 carries the
current of the second inductor 720.
FIG. 9 shows the transfer switch circuit 700 operating in a third
mode where the second inverter 704 provides power through the
transfer switch circuit 700 to the load 706 in standalone
operation. In particular, in the third mode, the third contact 712
is coupled between the second input 728 and the first output 730,
which allows power from the second inverter 704 to flow through the
third contact 712 and through the first inductor 718 to the load
706. Further, the fifth contact 716 is coupled between the second
input 728 and the second output 732, which allows power from the
second inverter 704 to flow through the fifth contact 716 and
through the second inductor 720 to the load 706. Note that the
first contact 708, the second contact 710, and the fourth contact
714 are not active (i.e., they do not connect an input to an
output) in the third mode. In the third mode of operation, since
only the second inverter provides power to the load, the total
power received from the power bus is provided by the second
inverter, and the power is evenly divided between the active
contacts (i.e., the third contact and the fifth contact) of the
transfer switch circuit 700. Correspondingly, each active contact
carries the current of one inductor. In particular, the third
contact 712 carries the current of the first inductor 718 and the
fifth contact 716 carries the current of the second inductor
720.
The transfer switch circuit 700 provides even current sharing among
active contacts in each of the three modes of operation.
Correspondingly, in each mode, each active contact carries one
inductor current. By evenly dividing power between active contacts
in each mode of operation, a power capability of the transfer
switch circuit may be increased relative to a circuit where all
power input to the circuit flows through a single contact (e.g.,
transfer switch circuit 400 of FIGS. 4-6 and transfer switch
circuit 1100 of FIGS. 11 and 12) instead of being evenly divided
between active contacts.
In some embodiments, the inductors and capacitors that filter the
power output from the transfer switch circuit may be positioned
between the inverters and the inputs of the transfer switch circuit
without departing from the scope of the present disclosure.
Further, it will be appreciated that the transfer switch circuit
may be implemented using contactors in addition to, or instead of
transfer switches without departing from the scope of the present
disclosure.
FIG. 10 shows a flow chart of an example method 1000 for
controlling a transfer switch circuit. In one example, the method
1000 is executed by the controller 126 in FIG. 1. At 1002, the
method 1000 includes, during a first mode of operation, controlling
a transfer switch circuit to transfer power from a first inverter
through a first contact of a transfer switch circuit and through a
first inductor to a load, and transfer power from a second inverter
through a second contact of the transfer switch circuit and through
a second inductor to the load. In the first mode of operation,
power from both of the first and second inverters is provided in
parallel to the load. The current of the inverters is shared evenly
between each of the first and second inductors.
At 1004, the method 1000 includes, during a second mode of
operation, controlling the transfer switch circuit to transfer
power from the first inverter through the first inductor and the
second inductor to the load, and transfer substantially no power
(e.g., less than 10% of a current output by the second inverter)
from the second inverter to the load. In the second mode of
operation, power from the first inverter is provided to the load
and the current of the first inverter is shared evenly between each
of the first and second inductors.
In some embodiments, at 1006, the method 1000 includes controlling
the transfer switch circuit to transfer power from the first
inductor through a third contact and through the first inductor to
the load, and transfer power from the first inductor through the
third contact, through a fourth contact, and through the second
inductor to the load in the second mode of operation. In one
example, such a step is performed when controlling the transfer
switch circuit 400 shown in FIGS. 4-6 to share current evenly
between the inductors.
In some embodiments, at 1008, the method 1000 includes controlling
the transfer switch circuit to divide power from the first inverter
between a third contact and a fourth contact in parallel to the
load. In one example, such a step is performed when controlling the
transfer switch circuit 700 shown in FIGS. 7-9 to share current
evenly between the active contacts and to share current evenly
between the inductors.
At 1010, the method 1000 includes, during a third mode of
operation, controlling the transfer switch circuit to transfer
power from the second inverter through the first inductor and the
second inductor to the load, and transfer substantially no power
from the first inverter to the load (e.g., less than 10% of a
current output by the first inverter).
In some embodiments, at 1012, the method 1000 includes controlling
the transfer switch circuit to transfer power from the second
inductor through a fifth contact and through the second inductor to
the load, and transfer power from the second inductor through the
fifth contact, through the fourth contact, and through the first
inductor to the load in the third mode of operation. In one
example, such a step is performed when controlling the transfer
switch circuit 400 shown in FIGS. 4-6 to share current evenly
between the inductors.
In some embodiments, at 1014, the method 1000 includes controlling
the transfer switch circuit to divide power from the second
inverter between the second contact and a fifth contact in parallel
to the load. In one example, such a step is performed when
controlling the transfer switch circuit 700 shown in FIGS. 7-9 to
share current evenly between the active contacts and to share
current evenly between the inductors.
By evenly sharing power among inductors and/or active contacts of
the transfer switch circuit during each mode of operation, the
power capacity of the circuit may be increased relative to a
transfer switch circuit that directs all power through a single
contact or a single inductor, under some conditions.
As used herein, an element or step recited in the singular and
proceeded with the word "a" or "an" should be understood as not
excluding plural of said elements or steps, unless such exclusion
is explicitly stated. Furthermore, references to "one embodiment"
of the present invention are not intended to be interpreted as
excluding the existence of additional embodiments that also
incorporate the recited features. Moreover, unless explicitly
stated to the contrary, embodiments "comprising," "including," or
"having" an element or a plurality of elements having a particular
property may include additional such elements not having that
property. The terms "including" and "in which" are used as the
plain-language equivalents of the respective terms "comprising" and
"wherein." Moreover, the terms "first," "second," and "third," etc.
are used merely as labels, and are not intended to impose numerical
requirements or a particular positional order on their objects.
This written description uses examples to disclose the invention,
including the best mode, and also to enable a person of ordinary
skill in the relevant art to practice the invention, including
making and using any devices or systems and performing any
incorporated methods. The patentable scope of the invention is
defined by the claims, and may include other examples that occur to
those of ordinary skill in the art. Such other examples are
intended to be within the scope of the claims if they have
structural elements that do not differ from the literal language of
the claims, or if they include equivalent structural elements with
insubstantial differences from the literal languages of the
claims.
* * * * *